EP 1 182 432 describes a flow sensor consisting of two housing parts for measuring the flow of fluids, which flow sensor comprises a semiconductor chip with sensor arrangement arranged between the housing parts. The semiconductor chip is located at a measuring channel configured as a groove in one of the housing parts. A sealing ring is additionally arranged between the housing parts. A strip conductor foil is guided outwards from the semiconductor chip between the sealing ring and the other one of the housing parts. Although the measuring channel is sealed by the sealing ring relative to the outside in the region of the gap between the housing parts, the measuring channel is not sealed relative to the gap between the housing parts.
A further flow sensor is described by Gruner A G, Bürglestrasse 15-17, 78564 Wehingen, Germany, this one consisting of two parts and a semiconductor sensor element. A measuring channel is again formed between the two parts, in which the sensor element is inserted. The two parts are adhesively bonded directly together, such that the measuring channel is for the most part sealed off from the gap between the two parts. It is however scarcely possible to achieve perfect sealing off of the measuring channel from the gap between the parts and at the same time completely to prevent penetration of adhesive into the measuring channel.
As a result of connections between the measuring channel and the gap between the housing parts and as a result of glue deposits in the measuring channel, dirt may accumulate, which may cause turbulent flow through the measuring channel and thus impair flow measurement quality.
US 2006/210445 A1 discloses a sensor comprising microfluidic channels, having lateral sealing lips made of resilient material. By arranging different microfluidic channels next to one another a high aspect ratio may be achieved.